DESCRIPTION: The applicant's long range goal is to contribute to understanding signal processing in the vertebrate ear. His approach is comparative, involving mammalian and amphibian subjects and involving five inner ear organs--including auditory sensors, vibratory sensors, and an equilibrium sensor. It is also integrative. He hopes to continue the top-down perspective needed to understand the mechanics of hearing and vestibular sensing. For the proposed project period, he plans to continue research in two areas, one experimental, one theoretical: (1) Adjustment of tuning and sensitivity in auditory, vibratory, and equilibrium sensors in response to changing ambient stimulus levels (2) Natural spectrograms and the role of axonal spike triggering in multiaxonal representations of temporal events in auditory and vibratory stimuli.